BELFAST, Northern Ireland Northern Ireland police used water cannons to fend off brick-hurling protesters in Belfast on Saturday as violent demonstrations over flying the British flag stretched into a third straight day.

Cars torched, firefighters attacked, police bombarded and neighbors terrified: It was another fine St. Patrick's Day in Ireland, where inebriated mobs annually turn districts of Dublin and Belfast into a nightmare.

Northern Ireland police arrested an Irish Republican Army suspect Tuesday over his alleged role in the killing of an undercover British soldier more than 30 years ago, one of the most controversial killings from the province's long conflict.